A liquid crystal display apparatus includes a liquid crystal display panel on which an image is displayed, and a light source device which illuminates the liquid crystal display panel from the back side of the liquid crystal display panel. A group of optical sheets (hereinafter also referred to as “optical sheet group”) are disposed between the liquid crystal display panel and the light source device. Light emitted from the front of the light source device is diffused, condensed and so forth by the optical sheet group, and enters the liquid crystal display panel.
In the description below, an example where the liquid crystal display panel is arranged in a vertical posture will be described.
The liquid crystal display panel is sandwiched and held between a frame-like support member (bezel, for example) at the front side and a frame-like support member (P chassis, for example) at the back side.
The light source device includes a light source formed of a fluorescent tube, an LED or the like, a light guide member such as a light guide plate or a diffusion plate which guides the light emitted by the light source to the back side of the display panel, and a backlight chassis (hereinafter referred to as BL chassis) which houses the light source and the light guide member.
A peripheral portion of the optical sheet group is disposed between the liquid crystal display panel and the P chassis, or between the P chassis and the BL chassis. Optical sheets constituting the optical sheet group are generally arranged in parallel with the liquid crystal display panel.
An optical sheet expands due to heat generated by the light source device. Thus, in the case where the peripheral portion of the optical sheet group is completely secured (held between the liquid crystal display panel and the P chassis, for example) along the entire periphery thereof, the optical sheets are prevented from expanding by heat, possibly causing flexure, wrinkles or the like therein.
In the case where the peripheral portion of the optical sheet group is not secured at all (e.g., is loosely inserted into a groove formed between the P chassis and the BL chassis), however, the optical sheets may slide over or collide against the liquid crystal display panel, which may possibly damage the liquid crystal display panel. The sliding or collision of the optical sheets occurs due to unwanted swaying (so-called fluttering) of the optical sheets that is caused by, for example, an external force applied to the liquid crystal display apparatus.
Conventionally, the liquid crystal display apparatus has been proposed that suppresses buckling of the optical sheet due to its own weight (see Japanese Patent Application Laid-Open Publication No. 2007-86648, which is hereinafter referred to as Patent Document 1).
The optical sheet according to Patent Document 1 is so curved that a middle part in the lateral direction is away from the liquid crystal display panel. As the curved optical sheet has a larger buckling load compared to a flat optical sheet, buckling of the optical sheet due to its own weight is suppressed.
The peripheral portion of the optical sheet according to Patent Document 1 is loosely inserted into a groove. Thus, the optical sheet is not easily deformed due to thermal expansion thereof. Moreover, since the optical sheet is so curved as to be away from the liquid crystal display panel, it will not easily slide over and collide against the liquid crystal display panel. Therefore, the liquid crystal display panel will not easily be damaged due to fluttering of the optical sheet.